Coming across fragments of bird egg shells in your garden, in the woods or when you're out and about can be an exciting find. But which birds do they come from?
This illustrated guide with our top tips will help you identify some of the more common shells you’re likely to find.
If you find egg remnants on the ground, they're likely to have been carried away after hatching by parent birds and discarded. They tend to drop them well away from their nests so they don't attract predators.
Please remember it is important not to disturb breeding birds and it's against the law to take their eggs.
Identification - egg shell colour
A clutch is a group of eggs that are laid at the same time. This can vary widely between species.
A brood is a set of young birds hatched at the same time by the same parents. As you'll see from this blog, some birds can have several broods each year, while others only have a single brood.
Different species have different eggs and with so many colours, sizes and shapes it can be difficult for us to tell whose is whose. In general, bird egg shells are made of calcium carbonate and so the default colour is white. But other pigments can cause eggs to take on different colours and patterns.
Birds that build their nests in trees and shrubs (like dunnock and blackbird) generally have blue or greenish eggs, either spotted or unspotted.
The eggs of hole-nesting birds are generally white or pale blue so that the parent birds can easily locate them and avoid breaking them. Egg camouflage is less important because the egg is usually well hidden within the nest.
Birds that lay their eggs in the open and on the ground rely on their eggs being very well camouflaged so usually produce brown or speckled eggs.
Carrion crows are large, all-black birds that prefer too lead a solitary life. They usually build their nests in the forks of trees and lay eggs between April-May.
Description:pale blue-green with brown and grey markings. Egg size:4.3 x 3cm Clutch size:4-7
Chaffinches are easily distinguished by their white wing-bar and their eggs are usually laid in spring from around April.
Description:off white eggs with brown-red splotches. Egg size:1.9 x 1.5 cm Clutch size:4-5
Now one of the UK's commonest birds, collared doves can have three or more broods, and can lay eggs from early in the year to the end of autumn.
Description:white-cream with no markings. Egg size:3.1 x 2.4 cm Clutch size:2
Also known as the hedge sparrow, these greyish birds will lay their eggs in a nest constructed of grass, leaves and roots. They can have several broods a year.
Description:light blue with no markings. Egg size:1.9 x 1.5 cm Clutch size:4-5
A brightly coloured finch with a red face and yellow wing patch. Goldfinch nests are neat and compact with a deep cup to prevent the eggs from being lost in high winds. They lay their eggs from late April and may have up to 2 to 3 broods.
Description: whitish with reddish-brown speckles. Egg size: 1.7 x 1.3 cm Clutch size: 4-6
This colourful bird is the UK's largest tit. It makes a nest of moss and feathers, before laying its eggs in early spring.
Description:white eggs with light brown-red speckles. Egg size:1.8 x 1.4 cm Clutch size:7-9
These small brown birds are often heard chirping away. Pairs will build nests of grass and straw before laying their eggs, usually in May. They can have several broods each year.
Description:white-light grey eggs with grey-brown markings. Egg size:2.2 x 1.6 cm Clutch size:4-5
Jackdaws are small black crows with a silvery sheen. They usually lay eggs during April-May, and have one brood a year.
Description:white/pale blue with grey and brown markings. Egg size:3.6 x 2.6cm Clutch size:4-5
Magpies, with their characteristic black and white plumage and long tail, can breed from as young as one year old and lay their eggs in early April.
Description:green-blue with brown markings. Egg size:3.2 x 2.3cm Clutch size:5-8
Pheasants, with their rich golden-brown plumage and long tails, were introduced to the UK as game birds. They are now widespread, nesting on the ground and lay their eggs during April-June.
Description:olive-brown with no markings. Egg size:4.5 x 3.6cm Clutch size:7-15
Description:white-cream eggs with light brown speckles. Egg size:2 x 1.5 cm Clutch size:4-5
Rooks are one of the first birds to nest, nest-building and laying eggs as early as the end of February-early March.
Description:green-blue with black/brown markings. Egg size:4 x 3cm Clutch size:3-9
Song thrushes are brown birds with paler underparts with darker drop-shaped spots. These relatives of the blackbird,begin to build their nest in early spring, twigs, moss and grass are used to make the round structure. They can have two to three broods.
Description:light blue eggs with black markings. Egg size:2.7 x 2 cm Clutch size:3-5
Noisy, glossy, shimmering birds, starlings nest in holes in trees and buildings and lay their eggs in mid-April.
Description:pale blue with no markings. Egg size:2.1 x 3cm Clutch size:4-6
Willow warblers can be found in woods, scrub and gardens. They are pale grey-green with a yellow underside. They build distinctive, dome-shaped nests which they lay their eggs in during April-May.
Description:white with reddish-brown markings. Egg size:1.5 x 1.3cm Clutch size:4-8
These are our largest pigeons and they inhabit woodland, parks, gardens and farmland throughout the UK. They are capable of breeding throughout the year, they will usually have one to two broods. The empty eggs of woodpigeons may often be seen lying on woodland floors and garden lawns.
Description:pure white with no markings. Egg size:4.1 x 2.9 cm Clutch size:2
One of the smallest birds in the UK, wrens begin to lay their eggs in April and can have two broods a year.
Description:white/light brown eggs with brown markings. Egg size:1.6 x 1.3cm Clutch size:5-6